1. Field of the Invention
The invention is related to an adjusting method of a computer system and memory, more particularly, to the adjusting method for changing a working frequency according to a phase difference of a control signal of the memory, and the computer system and the memory still execute stably while loading an operation system.
2. Description of the Related Art
With the requirements of multi-media development and the computer system revolution improves, the memory with higher speed, preferred function and lower power consumption is needed. Some kinds of memory technologies, such as Rambus DRAM, DDR SDRAM, and standard SDRAM for PC133 are competitiveness in the market. High speed memory such as DDR can be manufactured by conventional apparatuses, and will be the next generation of DRAM standard. For DDR, the speed of transmitting data is doubled to increase the speed of execution.
FIG. 1A is a time-domain diagram of Data Queue Strobe (DQS) signal of DDR in a normal status. Referred to FIG. 1A, in the normal status, the cross point of the DQS signal 102 and the reference voltage signal 104 is about the time point of the positive peak value A or the negative peak value B of the data timing signal 106. In other words, when the voltage differential value of the data timing signal 106 meets a maximum absolute value, the DQS signal 102 crosses with the reference voltage signal 104 for the memory executing stably.
FIG. 1B is a time-domain diagram of DQS signal in an overclock rate status. Referred to FIG. 1B, when a computer executes in either a higher clock rate or a lower clock rate compared with a normal status, the curves of the DQS signal 102 and the data timing signal 106 become deformed, not as the smooth curves that shown in FIG. 1A. At the moment, the cross point of the DQS signal 102 and the reference voltage signal 104 will not possible equal to the time point that meets a maximum absolute value of the voltage differential value of the data timing signal 106. As a result, the memory cannot work stably.